Plate heat exchanger and method for its manufacture

ABSTRACT

The invention relates to a method for the manufacture of a plate heat exchanger/cooler (1), and to an arrangement for a plate heat exchanger/cooler produced by furnace brazing. When finished, the heat exchanger exhibits a number of passageways (2-7) communicating in parallel via collectors (8a) and intended for a fluid which is cooled. Each of the passageways (2-7) consists of a pair of plates (2a, 2b, . . . 7a, 7b) facing one another. These have openings (2a2, 2b2, . . . 7a2, 7b2) arranged on the ends which, in the finished heat exchanger/cooler, constitute the aforementioned collectors (8a). Spacer washers (10) which define flow openings (10a) for a cooling medium are present between pairs of plates situated adjacent one another. The spacer washers (10) and the plates (2a, 2b, . . . 7a, 7b) and the pairs of plates are joined together at least along their outward-folded edges (2a1, 2b1, . . . 7a1, 7b1) by a furnace brazing process. In each passageway (2-7), a space washer (10) and a distance piece (11) are placed in an area on each end before the plates (2a, 2b, . . . 7a, 7b) are brought into edge-to-edge contact with one another. The plates and spacer washers/distance pieces (10;11) are caused by the furnace brazing process to form a solid body (12) on each short side of the heat exchanger/cooler (1). Before or after the furnace brazing process at least one transvers channel (9) for the installation of the heat exchanger cooler (1) is made through each such solid body (12).

The present invention relates to a method for the manufacture of a plateheat exchanger/cooler, which, in its finished state, exhibits a numberof passageways communicating in parallel via collectors and intended fora fluid which is to be cooled, each and every one of which passagewaysconsists of a pair of preferably rounded, rectangular plates executedwith projecting and outward-folded edges and facing one another, withopenings arranged on the short sides, which, in the finished heatexchanger/cooler, constitute the aforementioned collectors, inconjunction with which, on the one hand, spacer washers which defineslotted flow openings for a cooling medium are present between pairs ofplates situated adjacent to one another and, on the other hand, adistance piece is present between each pair of plates in an area on therespective short side, whereby the spacer washers and the plates and thepairs of plates are joined together at least along their outward-foldededges by a furnace brazing process.

For the sake of simplicity the expression cooler is used below for bothheat exchanger and cooler.

For the purposes of the installation of previously disclosed coolers ofthe aforementioned kind, they are provided with fastening devices, oftenin the form of fastening lugs or similar. These are usually attached toone of the outer plates of the cooler or take the form of projectingparts of the connection sleeves of the cooler. In order to be able toinstall the cooler in conjunction with a system of which it is a part,coolers of the previously disclosed kind require the fastening lugs toproject beyond the cooler. This means that the cooler takes up acomparatively large amount of space, due to the fact that more space isrequired than that which is needed by the actual cooler. This previouslydisclosed type of installation is also not ideal from the point of viewof its strength, since vibrations can give rise to fatigue damage, interalia at the point of attachment of the fastening lugs to the cooler.

A primary object of the present invention is to make available a methodfor the manufacture of a cooler which, for the purposes of itsinstallation, takes up less space than previously disclosed coolers.This is achieved through the invention, in that the spacer washers andthe distance pieces are positioned in the same area, in that theaforementioned plates and spacer washers/distance pieces are causedduring the furnace brazing operation to form a solid body on therespective short side of the plate heat exchanger/cooler, and in thatbefore or after the furnace brazing operation at least one channelrunning across the plates and through these and the spacewashers/distance pieces is produced in the aforementioned area, whichchannel is intended to be utilized in conjunction with the installationof the heat exchanger/cooler.

A cooler which is also considerably more resistant to vibration thanpreviously disclosed coolers is obtained via the method of manufacturein accordance with the invention.

The arrangement of spacers between the plates in dismantlable radiatorsmade of relatively thin plate is previously disclosed through, forexample, patent specification DE 122 393, patent application for publicinspection DE 1 172 828 and patent application FR 74 26 763. Thesespacers are arranged in areas where the plates are exposed to stressesfrom clamping braces by means of which the component parts of theradiator are held together. The spacers thus serve the purpose ofrelieving the stress on the radiator plates and of increasing therigidity of the radiator. The aforementioned publications do not revealthe presence of any solid body of the kind in accordance with theinvention.

Further characteristic features of the cooler in accordance with theinvention can be appreciated from the accompanying sub-claims and fromthe following description of the accompanying drawing, in which

FIG. 1 shows in perspective view one half of a cooler manufactured bythe method to which the invention relates.

FIGS. 2a, 2b and 2c show in that order a spacer washer, a distancepiece, and a part of a trough-shaped plate in a cooler in accordancewith FIG. 1.

FIG. 3 shows in perspective view a diagrammatic representation of apreferred method of manufacturing a cooler in accordance with theinvention.

FIG. 4 is a partial longitudinal section through the half of a coolershown in FIG. 1.

In the drawings, and especially in FIG. 1, the designation 1 is usedgenerally with respect to a cooler with six passageways 2-7 for a fluidwhich is to be cooled, which passageways are arranged adjacent to oneanother and at a certain distance from one another. These are connectedto one another in parallell and communicate with inlet and outletconnection sleeves 8 via collectors 8a. The sleeves 8 are executed in acommon fashion and are provided with an annular groove 8b for a seal,for example an `O`-ring. The fluid which is to be cooled thus passes viathe inlet connection coupling 8, the collector 8a, the passageways 2-7,the corresponding collector and the outlet connection coupling, thelatter two parts not being shown in the drawing. Each passageway 2-7consists of two preferably rounded rectangular plates 2a, 2b . . . 7a,7b, which are connected to one another in an airtight fashion, at leastalong their projecting and outward-folded edges 2a1, 2b1 . . . 7a1, 7b2.For the sake of clarity, only the plates 2a, 2b are shown in FIG. 3.

The ends of the plates 2a, 2b . . . 7a, 7b are provided with openings2a2, 2b2 . . . 7a2, 7b2, see FIG. 2c, which form the collectors 8a inthe finished cooler 1. The plates are joined together during manufactureby a process of furnace brazing. For the purposes of installing thecooler 1, channels 9 passing through same and through the coupling 8 areprovided in accordance with the invention. During operation, a coolingfluid is assumed to flow into the gap-like spaces, identified by thedesignation 1b in FIG. 4, through the passageways 2-7 which are arrangedat a certain distance from one another.

Reference is now made to FIG. 2 in order to explain in more detail acooler 1 produced in accordance with the invention. In this Figure thedesignations 10 and 11 are used respectively for spacer washers anddistance pieces, which are illustrated in detail in FIGS. 2a and 2b andare intended to be positioned in an area of the cooler 1 which issituated near the respective ends sides of the plates 2a, 2b . . . 7a,7b. The form of the space washers/distance pieces 10, 11 matches therounded ends of the plates 2a, 2b . . . 7a, 7b. The spacer washers 10define the distance between two passageways arranged adjacent to oneanother, i.e. the gap-shaped space between the passageways 2 and 3, 3and 4, and so on, intended for the cooling fluid. The distance pieceseffect the filling of a space situated immediately adjacent to therespective end of the passageways 2-7. As will be appreciated from FIGS.2a and 2b, the spacer washers 10 and the distance pieces 11 are executedwith recesses 10a and 11a, which interact with the openings 2a2, 2b2 . .. 7a2, 7b2 in the plates in order to form the collectors 8a. During thefurnace brazing process, in which the plates 2a, 2b . . . 7a, 7b areknown to be joined to one another at least along their edges, the plates2a, 2b . . . 7a, 7b, the coupling 8 and the spacer washers and thedistance pieces are also joined to one another in such a way that asolid body, generally designated 12, see FIG. 4, is formed on each endside of the cooler 1. The channels 9 are then made through this body,for example by conventional boring.

Another preferred method in accordance with the invention for making thechannels 9 will be appreciated from the following, with reference toFIG. 3: in conjunction with the pressing of the plates 2a, 2b . . . 7a,7b and the stamping out of the spacer washers and distance pieces 10,11, these are executed with symmetrically arranged transcurrent holes2a3, 2b3 . . . 7a3, 7b3; 10b and 11b. The designations 13, 14 are usedin respect of two pairs of mutually identical tubes, the externaldiameter of which is selected such that a sliding fit is obtainedbetween the aforementioned transcurrent holes and the pairs of tubes 13,14. During the manufacturing operation the tubes are arranged in anupright position, such that the plates 2a, 2b . . . 7a, 7b and thespacer washers/distance pieces 10, 11 can be slid onto the tubes in theintended sequence. One starts in this case with a spacer 10 on each ofthe pairs of tubes 13, 14. These are then followed by the plate 2a, thedistance piece 11, possibly a spacer body 15 designed to produce apredetermined type of flow in the chamber 2, the plate 2b, and then afurther spacer 10, and so on. Once a predetermined number of chambershas been produced, a coupling 8 is finally slid over the respective pairof tubes 13, 14, whereupon the tubes are upset at their ends by asufficient amount to ensure that the stacked plates and the spacerwashers/distance pieces are held securely to the couplings, whereuponthe furnace brazing operation takes place.

As already mentioned, the furnace brazing operation causes the plates2a, 2b. . . 7a, 7b to be joined together along their edges 2a1, 2b1 . .. 7a1, 7b1 with the respective spacer body 15 and in the respective areaof the short sides of the cooler with the spacers and the distancepieces 10, 11 and the coupling 8 and the pairs of tubes 13, 14, to forma solid body 12. The tubes 13, 14 in this case form the channels 9intended for the installation of the cooler.

We claim:
 1. Method for the manufacture of a plate heatexchanger/cooler, which, in its finished state, exhibits a number ofpassageways communicating in parallel via collectors and intended for afluid which is to be cooled, each and every one of which passagewaysconsists of a pair of preferably rounded, rectangular plates executedwith projecting and outward-folded edges and facing one another, withopenings arranged on the ends, which, in the finished heatexchanger/cooler, constitute the aforementioned collectors, inconjunction with which, on the one hand, spacer washers which defineflow openings for a cooling medium are present between pairs of platessituated adjacent to one another and, on the other hand, a distancepiece is present between each pair of plates in an area on therespective end, whereby the spacer washers and the plates and the pairsof plates are joined together at least along their outward-folded edgesby a furnace brazing process, characterized in that the spacer washersand the distance pieces are positioned in the same area, in that theaforementioned plates and spacer washers/distance pieces are caused bythe furnace brazing process to form a solid body on each end of the heatexchanger/cooler, and in that before or after the furnace brazingprocess at least one transcurrent channel running across the plates andthrough these and the spacer washers/distance pieces is produced in theaforementioned area, which channel is intended to be utilized inconjunction with the installation of the heat exchanger/cooler. 2.Method in accordance with claim 1, characterized in that each distancepiece and/or spacer washer is formed in such a way as to match the edgeof the end of the plate and is executed with a recess which interactswith the aforementioned collector.
 3. Method in accordance with claim 2,characterized in that the plates and the spacer washers/distance piecesare executed in conjunction with pressing and stamping out with twotranscurrent holes positioned symmetrically relative to the openings andthe recesses, in that during the manufacturing operation four tubes withan external diameter which permits a sliding fit in the aforementionedholes are arranged in an upright position, such that the plates and thespacer washers/distance pieces can be slid onto the tubes in theintended sequence, and in that once a predetermined number of plates andspacer washers/distance pieces has been stacked, the ends of the tubesare upset in order to ensure that the stacked plates and the spacerwashers/distance pieces are held securely together, whereupon thefurnace brazing operation takes place.
 4. Method in accordance withclaim 1, characterized in that the aforementioned transverse channelsintended for installation with the heat exchanger/cooler are made byconventional boring.
 5. Method in accordance with claim 1, characterizedin that a connection coupling is fixed by the furnace brazing process toeach collector on the outermost plate in question of the heatexchanger/cooler, and in that a spacer washer is fixed by the furnacebrazing process to the respective end of the opposite plate. 6.Arrangement for a plate heat exchanger/cooler produced by furnacebrazing, which has a number of passageways arranged adjacent to oneanother and at a certain distance from one another, with inlet andoutlet connection couplings for a fluid which is to be cooled andcommunicating in parallel, between which a cooling fluid is intended toflow, each of which passageways consists of two preferably roundedrectangular trough-shaped plates, which are connected to one another inan airtight fashion, characterized in that distance pieces and spacerwashers are present in an area on the respective ends of the passagewaysbetween the plates in each passage and between them, which distancepieces and spacer washers are caused during the furnace brazingoperation to form a solid body together with the plates and theconnection couplings, and in that there are present at each end twochannels arranged preferably symmetrically relative to the opening ofthe coupling, situated perpendicular to the plane of the plates andpassing through the aforementioned body, for the purpose of clamping theplate heat exchanger/cooler securely in position.
 7. Arrangement inaccordance with claim 6, characterized in that every aforementionedchannel through the respective solid body consists of a tube whichextends through the plates, the spacer washers/distance pieces and therespective coupling, and which is caused to become a part of theaforementioned body during the furnace brazing operation.
 8. Method inaccordance with claim 2, characterized in that the aforementionedtransverse channels intended for the installation the heatexchanger/cooler are made by conventional boring.
 9. Method inaccordance with claim 2, characterized in that a connection coupling isfixed by the furnace brazing process to each collector on the outermostplate in question of the heat exchanger/cooler, and in that a spacerwasher is fixed by the furnace brazing process to the respective end ofthe opposite plate.
 10. Method in accordance with claim 3, characterizedin that a connection coupling is fixed by the furnace brazing process toeach collector on the outermost plate in question of the heatexchanger/cooler, and in that a spacer washer is fixed by the furnacebrazing process to the respective end of the opposite plate.
 11. Methodin accordance with claim 4, characterized in that a connection couplingis fixed by the furnace brazing process to each collector on theoutermost plate in question of the heat exchanger/cooler, and in that aspacer washer is fixed by the furnace brazing process to the respectiveend of the opposite plate.